Such plate heat exchangers are generally known. Reference is made to DE 10 2009 030 095 A1, EP 0 623 798 A2 and EP 1 562 014 A1 as examples.
Such plate heat exchangers are typically used as oil cooler in motor vehicles, i.e., the oil to be cooled flows through the one chambers and the cooling water serving as cooling medium flows through the other chambers. With regard to good efficiency it is usually provided here that the fluids subjected to heat exchange are let flow in opposite flow directions in order to implement a heat exchange according to the counterflow principle. Alternatively, a so-called crossflow construction is also known in which the flow paths of the two flows cross each other diagonally in such a manner that the flow paths have great oppositely directed directional components.
Further plate heat exchangers are known, for example, from DE 10 2004 003 790 A1, DE 10 2010 001 828 A1, WO 2007/038871 A1, WO 2011/006825 A2 and WO 2011/011861 A1.
When used as an oil cooler of an internal combustion engine, the heat exchanger is usually held on stable parts of the engine housing, wherein in this case, load through engine vibrations becomes unavoidable.
In addition, loads caused by changing temperatures occur, which result to a lesser or greater extent in tensioning between adjacent plates. Since the trend in development of internal combustion engines currently and in the futures will go in the direction of internal combustion engines with small cubic capacity and a comparatively low number of cylinders, there is also a tendency towards increasing loads caused by temperature changes and vibrations.
In previous plate heat exchangers, the base plate or connecting plate was formed comparatively thick-walled and heavy and also extremely stiff, e.g., as a stamping. Nevertheless, after a certain operating time of the heat exchanger, cracks occurred in the connection region between the plate stack and the base or connecting plate so that it was not possible to achieve an operating time that matches the lifespan of the respective combustion engine.
This is where the invention starts, wherein a simple and light-weight construction is the aim.